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921.
The goals of the present study were twofold: first, to assess the renal excretory and hormonal responses to chronic water restriction in dogs whose sodium retaining mechanisms had been stimulated through dietary sodium (Na+) deprivation; second, to determine the mediator(s) of the natriuresis which was observed with water restriction in these sodium deprived dogs. Three groups of dogs maintained on a low Na+ diet (5 mEq/day) for two weeks underwent a three day period of water restriction. In normal, intact dogs Group 1 (N = 5), water restriction resulted in a significant increase in Na+ excretion with a net cumulative loss of 26.3 +/- 2.6 mEq over three days. The natriuresis was associated with a significant increase in plasma vasopressin (PAVP) (1.7 to 10.2 pg/mliter) and a significant fall in plasma aldosterone (PALDO) from the levels observed with Na+ restriction alone (24.9 to 12.4 ng/dliter). The natriuresis could not be explained by decreases in food intake as determined by control studies in four dogs. Group 2 (N = 6) dogs had a decrease in PALDO with water restriction that was prevented by means of continuous i.v. aldosterone infusion (6.0 micrograms/kg/day). Dogs in this group failed to demonstrate a natriuresis during three days of water restriction, despite the fact that PAVP rose from 3.3 +/- 0.8 to a peak level of 14.95 +/- 1.9 pg/mliter. Group 3 (N = 6) dogs underwent selective neurohypophysectomy, thus preventing the rise in PAVP during three days of water restriction. In this group, PALDO also remained unchanged from the Na+ deprived level during water restriction, and no natriuresis was observed. We conclude: 1) that the natriuresis which occurs with water restriction is a potent physiological response that occurs even in the Na+ restricted state; and 2) this natriuresis can be explained by a fall in PALDO and not the rise in PAVP. 相似文献
922.
923.
Genetic aspects of immotile cilia syndrome 总被引:3,自引:0,他引:3
J M Sturgess M W Thompson E Czegledy-Nagy J A Turner 《American journal of medical genetics》1986,25(1):149-160
The genetics of the immotile cilia syndrome has been analyzed in a series of 46 affected individuals from 38 families. Both sexes were equally affected: there were 20 males and 26 females in this series. All patients had upper and lower respiratory disease with chronic sinusitis, otitis, and chronic cough from early childhood. Bronchiectasis was common in older children and adults. Situs inversus occurred randomly, affecting 11 males and 15 females. Biopsies of nasal and bronchial mucosa from these subjects have been investigated by electron microscopy and identified as having specific ultrastructural defects of respiratory tract cilia including deficiencies in outer dynein arms (19), inner dynein arms (3), both inner and outer dynein arms (15), radial spoke defect (5); and microtubular transposition anomaly (4). Segregation analysis of proband sibships was consistent with autosomal recessive inheritance. However, the different ultrastructural defects that underly the immotile cilia syndrome involve presumably different genetic determinants, and the different types have not been analyzed separately. Examination of paternal age and birth order gave no evidence of new autosomal dominant mutation in the series. 相似文献
924.
925.
Hallucinations and associated factors in Alzheimer's disease. 总被引:1,自引:0,他引:1
D W Gilley M E Whalen R S Wilson D A Bennett 《The Journal of neuropsychiatry and clinical neurosciences》1991,3(4):371-376
In a consecutive sample of 230 community-dwelling patients with probable Alzheimer's disease, a structured interview yielded evidence of current hallucinations in 29.1% and misperceptions in another 11.3%. Visual and auditory modalities were similarly represented in apparent hallucinations. Hallucinations prior to the current monitoring period were rare among patients with misperceptions or with no perceptual abnormality. The probability of hallucinations was associated with the severity of cognitive dysfunction, the degree of other behavioral disturbances, and the presence of extrapyramidal signs. A logistic regression model predicting hallucinations based on these diverse clinical features accurately classified 87.0% of the sample. 相似文献
926.
Very little information is available concerning the pharmacology of type 2 astroglia. During the past decade it has become apparent that two distinct lineages of astroglial cells can be defined in vitro. These two lineages are commonly referred to as type 1 and type 2 and are distinguished from each other on the basis of their morphological features and antigenic phenotypes. In contrast to type 1 astroglia, very little is known about the pharmacology of type 2 astroglia. The lack of information concerning the responsiveness of these cells stems primarily from difficulties encountered in isolating large numbers of type 2 astroglia free of other cell types. In the present study video- and photometer-based imaging systems were used to monitor the influence of a series of neuroligands on the intracellular calcium levels of individual cerebral type 2 astroglia in order to assess their expression of calcium-mobilizing receptors. The responses of 85 immunocytochemically identified cerebral type 2 astroglia to bradykinin (BK), norepinephrine (NE), histamine (HIST), carbachol (CARB), 2-methyl-thio ATP (2MT-ATP), glutamate (GLUT), and serotonin (5-HT) were analyzed. Approximately 50% of cerebral type 2 astroglia responded to BK, NE, HIST, CARB, and 2MT-ATP whereas only 16% and 9% of the cells responded to GLUT and 5-HT, respectively. The number of neuroligands that increased calcium in individual cells ranged from 0 to 6. These responses are quite similar to those previously demonstrated in cultured cerebral type 1 astroglia. No pattern of receptor co-expression was observed for the different neuroligands tests.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
927.
Ramified microglial cells were investigated in primary cultures of dissociated cerebral cortical tissue from rats. The identification of these cells was confirmed through immunohistochemical staining with 7 monoclonal antibodies selective for microglia. While there was significant variation in staining intensity with different antibodies, all stained the identified ramified cells; the antibodies OX-42 and ED1 yielded the most intense immunoreactivity. Based on distinctive morphological features, the microglia could be identified in living cultures where they were monitored using time-lapse video recording. This technique revealed extremely dynamic features of cellular plasticity and motility. Ramified microglia exhibited constant and rapid alterations in the size and shape of their cell body with an associated extension and retraction of processes; concomitantly, the cells moved about in a circumscribed area. These features of plasticity and motility were unique to this cell type, and correlated with OX-42 immunostaining. The microglia also possessed a differentially high level of pinocytotic activity; this too was correlated with OX-42 staining. From the nature of their morphological plasticity and motility, high pinocytosis, and cellular distribution, it is hypothesized that the ramified microglia specifically function as a system of fluid cleansing in normal brain tissue. 相似文献
928.
929.
Dissociable roles of the ventral, medial and lateral striatum on the acquisition and performance of a complex visual stimulus-response habit. 总被引:3,自引:0,他引:3
The effects of discrete bilateral ibotenic acid lesions to 3 areas of striatum were examined on a conditional visual discrimination task involving temporal frequency (SLOW vs FAST flashes) that had previously been shown to be sensitive to the effects of dorsal striatal dopamine depletion. Two of the groups, namely, those with nucleus accumbens (ACC) and lateral caudate-putamen (LCP) lesions, were very disrupted in the acquisition of the task. The nature of the respective impairments of the 2 groups was dissociable, however. The performance of the ACC group could be improved either by manipulations of stimulus duration or inter-stimulus interval, implying an attentional deficit. In contrast, the rats with lesions of the LCP were not significantly improved by any of the behavioural challenges. Their performance was characterised by a bias to respond to the SLOW discriminandum. Under conditions of non-reward, the LCP group extinguished their responding at a similar rate to control rats whereas the ACC group were very much more persistent. Lesions of the medial caudate-putamen failed to affect any index of performance significantly. These data suggest that the LCP is necessary for the acquisition of arbitrary stimulus-response rules and that damage to an equivalent area in humans, such as in Huntington's disease, may explain deficits of procedural memory. The second part of the experiment investigated the effects of ACC lesions on established performance of the schedule. The lesioned group behaved identically to the ACC group that had been lesioned prior to acquisition, both in terms of accuracy and degree of persistence in extinction, further implying the role of attentional factors and inflexibility in the lesion-induced deficit. 相似文献
930.
Interethnic variation of drug metabolism 总被引:4,自引:0,他引:4
W Kalow 《Trends in pharmacological sciences》1991,12(3):102-107
There are many examples of differences between ethnically defined populations with regard to drug-metabolizing enzymes i.e. enzymes that serve as defences against exogenous chemicals. The prevalence of variants of enzymes such as monooxygenases, dehydrogenases, esterases and some transferases is not uniform, and this leads to differences in metabolism of drugs such as aspirin and diazepam, among others. Werner Kalow explains why the mere counting of a genetic variant may not be sufficient to uncover more major problems such as may be posed by multiple allelism or heterozygosity, and why it may be predicted that a large number of drugs will display interethnic differences in function. 相似文献